MONTPELIER — Two years ago, lawmakers endowed a five-person panel with the power to tell doctors how much they can charge patients for health care services. Now, some physicians with private practices say the rate-setting authority could put them out of business.

As part of a health care reform initiative launched under Gov. Peter Shumlin, lawmakers have intensified oversight of the medical industry, and granted unprecedented powers to a board that now regulates doctors and hospitals.

Among the licenses handed to the Green Mountain Care Board is the ability to set rates for physicians, and a handful of doctors flocked to the Statehouse last week to urge legislators to revoke that authority.

“When the state controls how doctors are paid, it opens the door for the state to use an elaborate system of financial rewards and punishments to manipulate the clinical decision-making of doctors,” said Dr. Robert Emmons, a psychiatrist with a private practice in Burlington.

Emmons and fellow doctors said imposing a ceiling on reimbursement rates would prevent doctors like him from providing the kind of premium care for which some patients are willing to pay higher prices.

“I believe we need private medicine in Vermont as an alternative for patients and doctors who expect the qualities of care that can be achieved within the framework of traditional clinical and ethical values,” Emmons said.

The Green Mountain Care Board will oversee the push toward single-payer health care in Vermont, a publicly financed system that Shumlin says he’ll have in place by 2017.

While the half-dozen doctors who spoke last week targeted the rate-setting authority specifically, their press event was organized by Vermonters for Health Care Freedom, a group dedicated to thwarting single-payer.

Robin Lunge, director of health care reform for the Shumlin administration, said decisions about patient care have already been wrested from most doctors by the insurance companies that determine how much they’ll be paid for various services and procedures.

“Do you think the insurance company is asking them how much money they’d like to get paid?” Lunge said. “No, the insurance company is telling them how much they’re going to pay.”

If rate-setting authority is placed in the hands of a public body, Lunge said, then the process used to determine reimbursement schedules will at least be visible to users of the system.

“What we’re looking to do is create some fairness and transparency in the system,” she said. “None of us has any idea when we go to a physician at a hospital how much it’s going to cost, and I think there’s a lot of interest in creating that kind of transparency. And the only way to create that transparency is in a systematic way.”

Dr. John Wheeler, a private plastic surgeon with practicing privileges at Rutland Regional Medical Center, said the state’s rate-setting authority goes further than it needs to accomplish Lunge’s goal. The law gives the Green Mountain Care Board the power to set rates not only for doctors who choose to participate in the single-payer system, but also those who opt to remain outside of it.

Wheeler said that if he and a patient want to negotiate a payment plan that allows for a level of physician attention made impossible by the high-volume traffic at conventional practices, then the government ought to leave them be.

“To be part of a larger group and told that I need to see a certain number of patients each and every day would not allow me this ability to work with individual patients, which I find so helpful,” Wheeler said. “Let us have our freedoms of individual practice.”

Mark Larson, commissioner of the Vermont Department of Health Access, says overhauling the systemwide shortcomings in the current system will require far-reaching policies.

“The authority was included in Act 48 so that as we move forward with an integrated health system that provides integrated coverage, that we can also manage costs, and make sure we’re getting the most for the dollars we spend,” Larson said.

Dr. Dick Butsch, a private surgeon who practices at Central Vermont Medical Center, said Vermont’s reform effort ought to be conducted in a way that doesn’t infringe on the relationship, financial and otherwise, between doctor and patient.

“And to say something is going to be illegal that we’ve done for so many years could be not very helpful, and in fact destructive,” Butsch said.

The Green Mountain Care Board has yet to invoke its rate-setting authority over any providers, let alone private physicians. And Lunge said if and when they do, it’s very possible that they’ll create exceptions for independent physicians like Emmons, Wheeler and Butsch. As the board proceeds with its deliberations, Lunge said, there will be plenty of opportunities to offer input and guidance — a privilege she said doctors don’t enjoy in the private-insurance model of health care.

“I think we are prejudging the board, and I don’t think there’s any evidence to assume they’re going to go to the most extreme, most punitive place,” Lunge said. “I think we should let them do their work, and see how it develops.”